The past decade has seen a “very significant” impact on M&As in the employee benefits space, Eissman says.

Among the implications? A more competitive landscape, for one. Smaller brokerage firms might be most at risk for survival. But the changes also are pushing them to adopt new ways of doing business, which could be an advantage in the long-run.

M&As also affect relationships between employers and brokers—but whether that's good or bad depends on a case-by-case basis.

Insurance-agency mergers and acquisitions hit an all-time high in 2012, with 291 transactions in the United States and Canada, according to OPTIS Partners, an investment-banking and financial-consulting firm.

But the biggest impact might be yet to come. Some experts predict the next few years will see an even bigger boom of M&A activity in the market.

“It was so fragmented and remains so fragmented that I think a lot is yet to come,” Eissman says.

That's in part because of continuing increased regulation in the benefits space, which has been spurring consolidation.

Then of course, there's the Patient Protection and Affordable Care Act, which is changing the game in many ways. Some firms have felt the need to affiliate with a buyer offering significant added value and other resources to compete in the changing marketplace in the wake of health reform.

Consolidation can help alleviate some pressure felt by economic and regulatory factors, so expect deal-making to continue, not subside.

“I think that confluence of factors will likely accelerate and magnify what has been happening in terms of M&As,” Eissman says.